Synchronism-indicator.



PATENTED MAY 9, 1905.

P. L. UT'IAREI.

SYNGHRONISM INDICATOR,

APPLICATION FILED OUT. 19! 1903. k

inventor.

Paul LCIarh Witnesses IUNITEU M Patented May 9, 1905.

tries.

PAUL L. CLARK, OF CHICAGO, ILLINOIS, ASSIGNOR TO GENERAL ELEC- TRIC COMPANY, A OOiPORA'ITION OF NEW YORK.

SYNCMROEWWEIWI IIWDECATUR.

SPECIFICATION forming part of Letters Patent No. 789,488, dated May 9, 1905.

Application filed October 19,1903. Serial No. 177,586.

To It 1/171/017'1/ it 77141.;1 con/(earn:

Be it known that I, PAUL L. CLARK, a citizen of the UnitedStates. residing at Chicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Synchronism-Tndicators, of which the following is a specification.

This invention relates to devices for ind icating the proper instant for closing the lineswitch of an alternating-current generator, synchronous motor, or rotary converter, which is to be connected in parallel with another similar machine already in operation. It is well understood that this must be done when 5 the machines are in step; but under ordinary conditions it is uncertain when that instant occurs. The machines are never thrown together when the indicating-lamps are liuctuating with short beats, and as the beats grow longer the interval of darkness or brightness,

as the case may be, extends over so long a period that it is (lIffiCUlt to guess just the right instant to close the switch.

My invention aims to eliminate any possi- 5 ble doubt on this score; and it consists in a signaling device, such as an indicating lamp orlamps controlled by a switch, which is kept open so long as the phase displacement is at a maximum and is closed by a solenoid only 5 when the beats become very long and at the middle portion only of each beat.

In the accompanyingdrawing is a diagram of circuits embodying my invention.

The machine A is connected with the leads 3 5 l 2 3 and is supposed to be running. The machine B is assumed to be coming up to speed, its leads 1 3 being open at the switch 4.

At 5 is an indicating lamp or lamps in a connection around the switch t and across 4 similar leads '1 1, so that when the machines are in step the lamps will be dark.

The lan'lp-circuit is controlled by a switch 6, which when no current is flowing is held normally closed by a yielding device, such as 4 5 a spring-arm7, fixed at one end. Adjustingscrews 8 8 enable the pressure of the switchcontacts to be varied. Connected with the arm 7 is the laminated core 90f asolenoid 10, which is connected m shunt to the lamps 5 andv switch 6, preferably through an adjust- 5 able resistance 11. The upper end of the core is suitably guided, preferably by a light springarm 7*, parallel with the arm 7. If desired,

a lamp or lamps 12 may be shunted around thelamps 5 and switch (3, though these are not essential.

The operation of my invention is as follows: When the machines are out of step and there is consequently an exchange of potential between them, the lamps 12 flash brightly, and the voltage across the solenoid is sutlicient to lift its core against the tension of the springs and open the switch 6, the vibration of the core being so rapid and so small that the switch remains open and no light appears in the lamps 5 5. As the speed and phase of machine B approach the speed and phase of machine A and the voltage across the line-switch drops the vibrating core 9 gradually drops until at some predetermined point when the machines are 7 nearly in step the spring-arm 7 causes the switch 6 to close the circuit of the lamps 5. The closing is only momentary, but is long enough for the lamps to glow dimly, but with a fading light which almostimmediately dies out. This is the instant for closing the lineswitch, for it is the point of the least difference in phase between the two machines. It the lamps 12 are used, they will act like or dinary series indicating-lamps and by this 30 flashing assist in determining the proper instant to close the line-switch; but instead of having to guess at the middle point of the long period of darkness the operator will be enabled by my device to judge of this point 5 very accurately, for the switchti is not closed until said point isnearly reached, and the subsequent and almost immediate darkening of the lamps is a close indication of the crossing of the waves.

In accordance with the patent statutes I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it 95 understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

hat I claim as new, and desire to secure by Letters Patent ot' the United States, is if 1. A synchronism-indicator comprising an electric signal responsive to exchange currents between machines to be synchronized, a solenoid in shunt to said signal, a solenoid-core controlling a switch in the signal-circuit, and a yielding support for said core.

2. A synchronism-indicator comprising an electric signal responsive to exchange currents between machines to be synchronized, a solenoid in shunt to said signal, a solenoid core controlling a switch in the signal-circuit, and an adjustable spring supporting said core.

3. A synchronism-indicator comprising an incandescent lamp or lamps responsive to exchange currents between machines to be synchronized, a solenoid in shunt to said lamps, a solenoid-core, a spring supporting said core, and a switch-contact carried by said spring and controlling the circuit of the lamps.

4. A synchronism-indicator comprising an electric signal responsive to exchange currents between machines to be synchronized, a solenoid in shunt to said signal, a solenoid -core controlling a switch in the signal-circuit, a yielding support for said core, and an adjustable resistance in circuit with the solenoid.

5. A synchronism'indicator comprising an electric signal responsive to exchange currents between machines to be synchronized, a solenoid in shunt to said signal, a solenoid -core controlling a switch in the signal-circuit, a yielding support for said core, and one or more electric lamps in shunt to the signal switch.

(5. ln a synchronism-indicator,means for energizing a signal only during the interval when the phase QliSPlEICBUlODt is at or near the mininzum.

7. In a synchronism-indicator, the combination of a signal, and acontrolling device responsive to exchange currents between the machines to be synchronized and operative to work said signal only when the phase displacement of the machines is at or near the minimum.

8. In a synchronizing device, the combination of a relay-magnet responsive to exchange currents between machines to besynchronized, and a circuit controlled by said relay, said circuit being held open by said magnet except when the exchange current is at or near a minimum.

In witness whereof I have hereunto set my hand this th day of October, 1903.

PAUL L. CLARK.

'Vitnesscs:

J. 'D. A. Onoss, N. Home 

